Tunnelling has started on Melbourne’s Suburban Rail Loop (SRL), with Terra Verde JV launching the first of four CREG TBMs that will excavate the northern section of the SRL East tunnels.
TBM Alice has started its drive from Burwood towards Glen Waverley, while a second machine, Hacia, has been lowered into the launch site and is expected to begin the parallel drive in the coming weeks.
Terra Verde, comprising Webuild, GS Engineering & Construction and Bouygues Construction Australia, was awarded the A$1.7bn Tunnels North contract to construct the twin tunnels between Glen Waverley and Box Hill. Its scope includes almost 10km of parallel tunnels, 39 cross passages, two station boxes, two TBM launch sites and an intervention and ventilation shaft.
Alice and Hacia are the first two of four TBMs being supplied by China Railway Engineering Equipment Group (CREG) for the northern tunnelling package. Manufactured in Zhengzhou, China, the machines have 7.25m-diameter cutterheads and are approximately 103m long in their initial configuration. The complete machines will extend to around 120m once assembly underground has been completed.
Because of the restricted space at Burwood, the machines are being started using an umbilical launch method, in what SRL says is a first for Victoria. The approximately 500t front shields were assembled at surface and lowered into the launch shaft before excavation began.
During the initial drive, the front section of each TBM operates connected to the surface by long cables and hoses providing power and support services. Once sufficient tunnel has been excavated, the remaining gantries and equipment are installed behind the shield to complete the machines.
The two machines will drive south from Burwood towards the Glen Waverley station box. Two further CREG TBMs will subsequently be launched from Burwood in 2027 to excavate north towards Box Hill. Collectively the four machines will excavate more than 10km for the northern section.
Meanwhile, the southern tunnelling package between Cheltenham and Glen Waverley is being delivered by the Suburban Connect consortium of CPB Contractors, Ghella and Acciona Construction.
Four 7.24m-diameter Herrenknecht TBMs will excavate approximately 16km of twin tunnels on this section. Two of the machines are new, while two are being refurbished following their use on Sydney Metro. Different machine configurations will be used to deal with changing ground conditions, including slurry operation and machines capable of conversion to EPB mode in softer ground towards Cheltenham.
The first southern machine, Aayushi, is currently being assembled at Clarinda and is scheduled to begin tunnelling towards Glen Waverley later this year. Further machines will subsequently drive towards Cheltenham via the Heatherton stabling facility.
In total, eight TBMs will excavate the 26km of twin tunnels forming SRL East between Cheltenham and Box Hill. The tunnels will run at an average depth of around 26m and reach approximately 60m below ground at their deepest point.
Major construction is underway at all six SRL East station sites – Cheltenham, Clayton, Monash, Glen Waverley, Burwood and Box Hill.
The Victorian Government said tunnelling had started on schedule. It has identified A$1bn in project savings and commissioned an independent technical review aimed at finding a further A$1bn.
SRL East is scheduled to open to passengers in 2035 and will form the first section of Melbourne’s planned orbital rail network.
Comments:
Facts Only
* Terra Verde JV launched four CREG TBMs for the northern section of the SRL East tunnels.
* TBM Alice is driving from Burwood towards Glen Waverley.
* TBM Hacia is being lowered into the launch site to begin a parallel drive.
* Terra Verde was awarded the A$1.7bn Tunnels North contract to construct twin tunnels between Glen Waverley and Box Hill.
* The scope of the contract includes almost 10km of parallel tunnels, 39 cross passages, two station boxes, two TBM launch sites, and an intervention/ventilation shaft.
* TBM Alice and Hacia are two of four TBMs supplied by CREG, manufactured in Zhengzhou, China.
* The complete machines will extend to approximately 120m long after underground assembly is complete.
* AUMail launch method was used at Burwood, involving the assembly and lowering of approximately 500t front shields before excavation.
* Two southern tunnelling packages are underway: between Cheltenham and Glen Waverley and the northern section for SRL East.
* Four Herrenknecht TBMs will excavate approximately 16km of twin tunnels on the southern section.
* In total, eight TBMs will excavate the 26km of twin tunnels forming SRL East between Cheltenham and Box Hill.
* The tunnels are scheduled to be around 26m deep, reaching approximately 60m below ground at their deepest point.
* Construction is underway at six station sites: Cheltenham, Clayton, Monash, Glen Waverley, Burwood, and Box Hill.
Executive Summary
Terra Verde JV is undertaking the excavation of the northern section of Melbourne’s Suburban Rail Loop (SRL) East tunnels using Tunnel Boring Machines (TBMs). The project involves four CREG TBMs, Alice and Hacia, which are being supplied by China Railway Engineering Equipment Group (CREG). These machines will construct twin tunnels between Glen Waverley and Box Hill, covering almost 10 kilometers.
The tunnelling package is divided into two sections: the northern section for SRL East and the southern section between Cheltenham and Glen Waverley. The northern work involves four TBMs to excavate over 10km. The southern section is being handled by the Suburban Connect consortium using four Herrenknecht TBMs, which will excavate approximately 16km of twin tunnels.
Eight TBMs will collectively excavate the 26km of twin tunnels forming SRL East between Cheltenham and Box Hill, aiming for an average depth of around 26 meters. Major construction is proceeding at six station sites: Cheltenham, Clayton, Monash, Glen Waverley, Burwood, and Box Hill. The Victorian Government noted tunnelling commenced on schedule and identified project savings, with a subsequent review commissioned for further savings. The SRL East section is planned to open in 2035 as part of the orbital rail network.
Full Take
The narrative presents a complex logistical feat where cutting-edge heavy machinery meets large-scale public infrastructure development under tight timelines. The pattern observed is the coupling of specialized international technology (CREG TBMs) with local contracting bodies (Terra Verde JV) to achieve an ambitious, time-bound goal (2035 opening). This juxtaposition highlights the tension between technological capability and real-world execution risk management across geographically diverse projects.
The division between the northern and southern tunnelling packages illustrates a segmented, parallel effort, which inherently introduces complexity in coordination and contingency planning. The difference in machine specification—CREG TBMs versus Herrenknecht TBMs—and the adaptation for changing geology (slurry vs. EPB mode) suggests that the execution is not a monolithic process but requires specialized problem-solving tailored to local conditions.
The call for A$1bn in savings, followed by commissioning an independent review for another A$1bn, signals a strategic need to manage project scope and cost while maintaining public confidence regarding the schedule. The structure of moving from initial localized drives (Alice) to subsequent planned launches (2027) forces the system into a pattern of staged, iterative risk exposure rather than a single, predictable delivery curve.
The implication is that large-scale infrastructure projects succeed not purely on engineering prowess, but on the management of systemic friction—the synchronization of international supply chains, the adaptation to variable ground conditions across different geographical zones, and the political navigation required to secure further funding for necessary risk mitigation. What systems are in place to ensure that the coordination between TBM operations from Burwood through Box Hill is robust enough to handle unforeseen geological variance while maintaining the overall 2035 target? What metrics govern the transition and integration of these disparate tunneling phases?
Sentinel — Human
This text reads as factual reporting, detailing the technical scope and status of significant infrastructure projects, consistent with professional journalistic output.